Map information system

ABSTRACT

A map information system includes a map database including map information; and a driving assist level determination device. The map information is associated with an evaluation value indicating a certainty of the map information for each location in an absolute coordinate system. Information indicating that the intervention operation is performed is included in driving environment information indicating a driving environment of a vehicle. The driving assist level determination device is configured to acquire, based on the driving environment information, intervention operation information indicating an intervention operation location where the intervention operation is performed, acquire, based on the map information, the evaluation value for each point or section in a target range, and determine, based on the evaluation value and the intervention operation location, an allowable level for each point or section within the target range.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No.17/514,718 filed Oct. 29, 2021, which is a Continuation of U.S.application Ser. No. 16/660,274 filed Oct. 22, 2019, which claimspriority based on Japanese Patent Application No. 2019-008828 filed onJan. 22, 2019 and Japanese Patent Application No. 2018-208232 filed onNov. 5, 2018, the disclosures of which are incorporated herein byreference in its entirety.

BACKGROUND 1. Technical Field

The present disclosure relates to a map information system.

2. Description of Related Art

WO 2016/139748 discloses a route searching device that notifies a userabout a location unsuitable for autonomous driving. A locationunsuitable for autonomous driving is a location where the detectionaccuracy of a sensor does not satisfy criteria that are set foracquiring periphery information necessary for autonomous driving.Examples of the location unsuitable for autonomous driving may include aheavy rain section, a road surface freezing section, a dense fogsection, and a section where a lane marking or an indicator isundetectable with a sensor. The route searching device predicts thelocations unsuitable for autonomous driving, and notifies a user aboutthe predicted locations unsuitable for autonomous driving.

U.S. Pat. No. 8,676,430 discloses a vehicle that performs autonomousdriving based on map information. Whether the map information isinadequate or not is determined by comparing the map information withsensor detection information. When the map information is determined tobe inadequate, the vehicle performs autonomous driving with use ofsensor detection information as additional information, whileencouraging the user to switch to manual driving.

U.S. Pat. No. 8,825,264 discloses a technique related to zone driving byan autonomous driving system. In the technique, a road map (road graph)includes zones associated with specific rules. When a vehicle approachesa zone, the autonomous driving system notifies a driver that the vehicleis approaching the zone, and requests the driver to perform control(steering, acceleration and deceleration) corresponding to the specificrules.

Japanese Patent Application Publication No. 2018-088060 discloses anautonomous driving device that executes autonomous driving control of avehicle. The autonomous driving device switches operating states of thevehicle, between an autonomous driving state and a semiautonomousdriving state, in consideration of the location where the vehicletravels.

Japanese Patent Application Publication No. 2007-101690 discloses a mapupdating device mounted on a vehicle. Map information includes roadgeometries and locations of a plurality of marks. The map updatingdevice detects a mark in the periphery of the vehicle with a sensor, andestimates a vehicle location with a high degree of accuracy with use ofthe detected mark. The map updating device calculates road geometriesbased on the estimated vehicle location, and updates the map informationbased on the road geometries.

WO 2017/051478 discloses a driving assist device. A map database storesmap data. The map data includes driving automation levels indicating theautomation levels of autonomous driving control that are associated withevery predetermined section of the roads. The driving assist devicegenerates guiding information corresponding to the driving automationlevel in a current location of an own vehicle and in front of the ownvehicle. For example, the driving assist device displays information ona change point of the driving automation levels.

SUMMARY

Driving assist control that assists driving of a vehicle will beconsidered. As the level of the driving assist control becomes higher,the load of a driver of the vehicle is lessened more. It is preferable,from a perspective of the convenience of the driver, to automaticallydetermine an appropriate level of driving assist control.

The present disclosure provides a map information system capable ofautomatically determining an appropriate level of driving assist controlthat assists driving of a vehicle.

A first aspect of the present disclosure map is an information system.The system includes: a map database and a driving assist leveldetermination device. The map database includes map information used fordriving assist control for assisting driving of a vehicle. The drivingassist level determination device is configured to determine anallowable level of the driving assist control that is allowed when thevehicle travels in a target range. The map information is associatedwith an evaluation value indicating a certainty of the map informationfor each location in an absolute coordinate system. The driving assistlevel determination device is configured to acquire, based on drivingenvironment information indicating a driving environment of the vehicle,intervention operation information indicating an intervention operationlocation that is a location where an intervention operation isperformed, the intervention operation being an operation performed by adriver of the vehicle to intervene in the driving assist control duringexecution of the driving assist control, the driving environmentinformation including information indicating that the interventionoperation has been performed, acquire, based on the map information, theevaluation value for each point or section within the target range, anddetermine, based on the evaluation value and the intervention operationlocation, the allowable level for each point or section within thetarget range.

In the map information system according to the first aspect, theallowable level in the intervention operation location may be equal toor less than the allowable level in a normal location that is not theintervention operation location, on condition that the evaluation valuesin the intervention operation location and the normal location areidentical.

In the above configuration, the driving assist level determinationdevice may be configured to set the allowable level to a first level inthe location where the evaluation value is less than a threshold, setthe allowable level to a second level that is higher than the firstlevel in the location where the evaluation value is equal to or morethan the threshold, and increase the threshold in the interventionoperation location so as to be larger than the threshold in the normalposition.

In the above configuration, the driving assist level determinationdevice may be configured to maintain the evaluation value in the normalposition while reducing the evaluation value in the interventionoperation location so as to acquire a corrected evaluation value, setthe allowable level to a first level in the location where the correctedevaluation value is less than a threshold, and set the allowable levelto a second level that is higher than the first level in the locationwhere the corrected evaluation value is equal to or more than thethreshold.

The map information system according to the first aspect may furtherinclude a database management device configured to manage the mapdatabase. The database management device may be configured to acquirethe intervention operation information from the driving environmentinformation, and update the map database so as to reduce the evaluationvalue in the intervention operation location. The driving assist leveldetermination device may be configured to set the allowable level to afirst level in the location where the evaluation value is less than athreshold, and set the allowable level to a second level that is higherthan the first level in the location where the evaluation value is equalto or more than the threshold.

The map information system according to the above configuration mayfurther include a driving assist controller configured to perform thedriving assist control of the allowable level, based on the drivingenvironment information and the map information.

The map information system according to the above configuration mayfurther include a display device mounted on the vehicle. The drivingassist level determination device may be configured to determine theallowable level along the target route for the vehicle to travel. Thedriving assist controller may be configured to display on the displaydevice a transition of the allowable level from a current location orcurrent time.

A second aspect of the present disclosure is a map information system.The system includes: a storage device and one or more processors. Thestorage device is configured to store a map database including mapinformation used for driving assist control for assisting driving of avehicle. The map information is associated with an evaluation valueindicating a certainty of the map information for each location in anabsolute coordinate system. The one or more processors are configured toacquire, based on driving environment information indicating a drivingenvironment of the vehicle, intervention operation informationindicating an intervention operation location that is a location wherean intervention operation is performed, the intervention operation beingan operation performed by a driver of the vehicle to intervene in thedriving assist control during execution of the driving assist control,the driving environment information including information indicatingthat the intervention operation has been performed, acquire, based onthe map information, the evaluation value for each point or section in atarget range, and determine, based on the evaluation value and theintervention operation location, an allowable level of the drivingassist control that is allowed when the vehicle travels within thetarget range, for each point or section within the target range.

In the map information system according to the second aspect, theallowable level in the intervention operation location may be equal toor less than the allowable level in a normal location that is not theintervention operation location, on condition that the evaluation valuesin the intervention operation location and the normal location areidentical.

According to the first and second aspects, the driving assist leveldetermination device automatically determines the allowable level of thedriving assist control within a target range. The driving assist leveldetermination device determines the allowable level based on theevaluation value of the map information in particular. Since theevaluation value of the map information is taken into consideration, theallowable level is appropriately determined. As a result, theconvenience for the driver of the vehicle is enhanced.

Furthermore, the driving assist level determination device determinesthe allowable level of the driving assist control based on theintervention operation location. The intervention operation representsthe intention of a driver to drive. In the location where theintervention operation is performed, there is a possibility that aphenomenon undesirable for the driving assist control may be present.Therefore, taking the intervention operation location into considerationmakes it possible to more appropriately determine the allowable level inthe intervention operation location.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, advantages, and technical and industrial significance ofexemplary embodiments of the disclosure will be described below withreference to the accompanying drawings, in which like numerals denotelike elements, and wherein:

FIG. 1 is a conceptual view for describing a vehicle according to anembodiment of the present disclosure;

FIG. 2 is a conceptual view for describing an example of a plurality ofdriving assist levels in the embodiment of the present disclosure;

FIG. 3 is a block diagram conceptually showing the configuration of amap information system according to the embodiment of the presentdisclosure;

FIG. 4 is a conceptual view for describing an example of map informationin the embodiment of the present disclosure;

FIG. 5 is a conceptual view for describing an example of a determinationmethod of an allowable level by a driving assist level determinationdevice according to the embodiment of the present disclosure;

FIG. 6 is a conceptual view for describing another example of thedetermination method of the allowable level by the driving assist leveldetermination device according to the embodiment of the presentdisclosure;

FIG. 7 is a block diagram schematically showing another example of theconfiguration of the map information system according to the embodimentof the present disclosure;

FIG. 8 is a conceptual view for describing still another example of thedetermination method of the allowable level by the driving assist leveldetermination device according to the embodiment of the presentdisclosure;

FIG. 9 is a conceptual view for describing yet another example of thedetermination method of the allowable level by the driving assist leveldetermination device according to the embodiment of the presentdisclosure;

FIG. 10 is a block diagram showing a configuration example of a drivingassist controller according to the embodiment of the present disclosure;

FIG. 11 is a block diagram showing an example of driving environmentinformation used in the embodiment of the present disclosure;

FIG. 12 is a block diagram showing a first configuration example of adatabase management device according to the embodiment of the presentdisclosure;

FIG. 13 is a block diagram showing a second configuration example of thedatabase management device according to the embodiment of the presentdisclosure;

FIG. 14 is a block diagram showing a third configuration example of thedatabase management device according to the embodiment of the presentdisclosure;

FIG. 15 is a block diagram showing a first configuration example of thedriving assist level determination device according to the embodiment ofthe present disclosure;

FIG. 16 is a block diagram showing a second configuration example of thedriving assist level determination device according to the embodiment ofthe present disclosure;

FIG. 17 is a block diagram showing a third configuration example of thedriving assist level determination device according to the embodiment ofthe present disclosure;

FIG. 18 is a flowchart showing registration of intervention operationinformation by the database management device according to theembodiment of the present disclosure;

FIG. 19 is a flowchart showing a first example of the determinationmethod of the allowable level of the driving assist control according tothe embodiment of the present disclosure;

FIG. 20 is a flowchart showing a second example of the determinationmethod of the allowable level of the driving assist control according tothe embodiment of the present disclosure;

FIG. 21 is a flowchart showing a third example of the determinationmethod of the allowable level of the driving assist control according tothe embodiment of the present disclosure;

FIG. 22 is a flowchart showing a fourth example of the determinationmethod of the allowable level of the driving assist control according tothe embodiment of the present disclosure;

FIG. 23 is a block diagram showing various examples of map informationin the embodiment of the present disclosure;

FIG. 24 is a conceptual view for describing an example of stationaryobject map information in the embodiment of the present disclosure;

FIG. 25 is a conceptual view for describing an example of terrain mapinformation in the embodiment of the present disclosure;

FIG. 26 is a conceptual view for describing an example of characteristicobject map information in the embodiment of the present disclosure;

FIG. 27 is a conceptual view for describing an example of own-locationestimation in the embodiment of the present disclosure;

FIG. 28 is a conceptual view for describing an example of own-locationestimation in the embodiment of the present disclosure;

FIG. 29 is a conceptual view for describing an example of track mapinformation in the embodiment of the present disclosure;

FIG. 30 is a flowchart showing a map information updating process by thedatabase management device according to the embodiment of the presentdisclosure;

FIG. 31 is a conceptual view showing an example of display of allowablelevels in the embodiment of the present disclosure;

FIG. 32 is a conceptual view showing another example of the display ofthe allowable levels in the embodiment of the present disclosure; and

FIG. 33 is a conceptual view showing still another example of thedisplay of the allowable levels in the embodiment of the presentdisclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

The embodiments of the present disclosure will be described below withreference to the accompanying drawings.

1. Outline 1-1. Driving Assist Control

FIG. 1 is a conceptual view for describing a vehicle 1 according to anembodiment. The vehicle 1 is mounted with an information acquisitiondevice 20 and a driving assist controller 100.

The information acquisition device 20 acquires various pieces ofinformation using a sensor mounted on the vehicle 1. The informationacquired with the sensor mounted on the vehicle 1 is the informationindicating a driving environment of the vehicle 1. Hereinafter, theinformation is called “driving environment information 200.” Forexample, the driving environment information 200 includes vehiclelocation information indicating the location of the vehicle 1, vehiclestate information indicating the state of the vehicle 1, and peripheralcondition information indicating the conditions around the vehicle 1.

The driving assist controller 100 performs driving assist control forassisting driving of the vehicle 1 based on the driving environmentinformation 200. The driving assist control typically includes at leastone of steering control, acceleration control, and deceleration control.Examples of such driving assist control may include autonomous drivingcontrol, path-following control, lane tracing assist control, collisionavoidance control, and adaptive cruise control (ACC).

In the driving assist control, map information MAP is often used. Themap information MAP provides various pieces of information associatedwith location. The location is an absolute location defined in anabsolute coordinate system (latitude, longitude, and altitude). The mapinformation MAP is not limited to general road maps or navigation maps.Rather, the map information MAP may include maps in variousperspectives. For example, the map information MAP may indicates thelocation of stationary objects (example: guardrails and walls) on roads,road surfaces, and characteristic objects (example: lane markings,poles, and signboards).

In the present embodiment, the driving assist control is classified intoa plurality of levels (stages). The levels of the driving assist controlare hereinafter called “driving assist levels.” Among the driving assistlevels, the height of the levels can be compared. In the higher drivingassist level, the driving assist controller 100 performs more drivingoperations. It can be said that the driving assist levels represent thedegrees (commission degrees) that a driver commits the driving of thevehicle 1 to the driving assist controller 100.

FIG. 2 is a conceptual view for describing an example of the drivingassist levels. A driving assist level LV-A is the lowest, and a drivingassist level LV-E is the highest. For example, the contents of thedriving assist levels LV-A to LV-E are as follows.

[LV-A] Driving assist control without using the map information MAP(example: adaptive cruise control).

[LV-B] Limited driving assist control using the map information MAP(example: adaptive cruise control+lane tracing assist control).

[LV-C] Driving assist control using the map information MAP. The drivingassist controller 100 performs steering control. A driver may put thehands off the steering wheel (hands-off). The driver is required tomonitor the conditions around the vehicle 1. The driver performs manualdriving as necessary.[LV-D] Driving assist control using the map information MAP. The drivingassist controller 100 performs steering control, acceleration control,and deceleration control. The driver does not need to monitor theconditions around the vehicle 1 (eyes-off). However, at the time ofemergency, the driving assist controller 100 issues “transition demand”that is a demand for the driver to start manual driving. In response tothe transition demand, the driver starts manual driving within aprescribed time.[LV-E] Driving assist control using the map information MAP. The drivingassist controller 100 performs steering control, acceleration control,and deceleration control. The driver does not need to monitor theconditions around the vehicle 1. At the time of emergency, the drivingassist controller 100 automatically retreats the vehicle 1 to a safelocation.

The classification of the driving assist levels is not limited to theclassification shown in FIG. 2 . For example, each of the driving assistlevels may further be divided into subdivisions. In another example, theclassification of the driving assist levels may coincide with theclassification of generally used autonomous driving levels.

The accuracy of the driving assist control is dependent on the qualityof the map information MAP. As the quality of the map information MAP isimproved more, the accuracy of the driving assist control becomeshigher, which makes it possible to conduct the driving assist control ofa higher level. Hereinafter, a map information system that handles themap information MAP will be described.

1-2. Summary of Map Information System

FIG. 3 is a block diagram schematically showing the configuration of themap information system 10 according to the embodiment of the presentdisclosure. The map information system 10 is a system that manages anduses the map information MAP. More specifically, the map informationsystem 10 includes a map database MAP_DB, the information acquisitiondevice 20, a database management device 30, and a driving assist leveldetermination device 40. The map information system 10 may furtherinclude the aforementioned driving assist controller 100.

The map database MAP_DB is an assembly of the map information MAP thatis used for the driving assist control. The map database MAP_DB may bestored in a storage device of the vehicle 1, or may be stored in anexternal device outside the vehicle 1.

The database management device 30 manages the map database MAP_DB. Morespecifically, the database management device 30 acquires the drivingenvironment information 200 from the information acquisition device 20,and manages the map database MAP_DB based on the driving environmentinformation 200. Management of the map database MAP_DB includes at leastone of generation and update of the map information MAP. The managementof the map database MAP_DB may include sharing of the map informationMAP. The generation and update of the map information MAP will bedescribed in detail in Sections 5 and 6 described later.

The database management device 30 may be mounted on the vehicle 1, or beincluded in an external device outside the vehicle 1. Alternatively, thedatabase management device 30 may be disposed in the vehicle 1 and theexternal device in a distributed manner.

The driving assist level determination device 40 automaticallydetermines the driving assist level that is allowed when the vehicle 1travels in a target range. For example, the target range is a rangealong a target route for the vehicle 1 to travel. An allowable maximumdriving assist level is hereinafter called “allowable level ALV.” Asdescribed before, as the quality of the map information MAP is improvedmore, the accuracy of the driving assist control becomes higher, whichmakes it possible to conduct the driving assist control of a higherlevel. Therefore, the driving assist level determination device 40automatically determines the allowable level ALV of the driving assistcontrol at least based on the map information MAP.

The driving assist level determination device 40 may be mounted on thevehicle 1, or be included in an external device outside the vehicle 1.Alternatively, the driving assist level determination device 40 may bedisposed in the vehicle 1 and the external device in a distributedmanner.

The driving assist controller 100 performs driving assist control basedon the driving environment information 200 and the map information MAP.At the time, the driving assist controller 100 performs driving assistcontrol of an allowable level ALV that is determined by the drivingassist level determination device 40.

Hereinafter, the determination method of the allowable level ALV by thedriving assist level determination device 40 will be described in moredetail.

1-3. Determination of Acceptable Level Based on Map Information

The map information MAP is associated with a location (absolutelocation) in an absolute coordinate system. According to the presentembodiment, the map information MAP is further associated with“evaluation value P” indicating “certainty” of the map information MAPfor each location in the absolute coordinate system. The certainty canalso be expressed as accuracy or reliability. The evaluation value P canalso be expressed as a score.

FIG. 4 is a conceptual view for describing an example of the mapinformation MAP in the present embodiment. In the example shown in FIG.4 , the map information MAP includes base map information and theevaluation value P. The base map information is associated with anabsolute location. The base map information is main information on themap information MAP. The evaluation value P indicates a certainty of thebase map information in terms of the absolute location. Base mapinformation and an evaluation value P associated with the base mapinformation constitute one data set.

For example, in the case of the map information MAP that indicates thelocation of a characteristic object, the base map information isinformation itself that indicates the location of the characteristicobject. The evaluation value P indicates a certainty of thecharacteristic object present in the location indicated by the base mapinformation. Various examples of the map information MAP and theevaluation value P will be described in detail in Section 5 later.

In the following description, the evaluation value P becomes higher asthe certainty of the map information MAP is higher. However, the mapinformation system may be designed such that the evaluation value Pbecomes higher as “uncertainty” of the map information MAP is higher(certainty is lower). In that case, the phrase “the evaluation value Pis higher” is deemed to be replaced with “the evaluation value P islower.”

As the evaluation value P of the map information MAP is higher, theaccuracy of the driving assist control using the map information MAPbecomes higher, which makes it possible to conduct the driving assistcontrol of a higher level. Therefore, in the present embodiment, theallowable level ALV of the driving assist control is determined inconsideration of the evaluation value P of the map information MAP.

FIG. 5 is a conceptual view for describing an example of thedetermination method of the allowable level ALV. A horizontal axisrepresents a location within the target range where the vehicle 1travels. A vertical axis represents the evaluation value P.

As shown in FIG. 5 , a threshold TH is set for each of the drivingassist levels. The threshold TH is a minimum evaluation value P requiredto conduct the driving assist control of each of the driving assistlevels with sufficient accuracy. In other words, the threshold TH is theminimum evaluation value P required to allow each of the driving assistlevels. For example, a threshold TH-C is the minimum evaluation value Prequired to allow the driving assist level LV-C. When the evaluationvalue P is less than the threshold TH-C, the driving assist level LV-Cis not allowed. When the evaluation value P is equal to or more than thethreshold TH-C, the driving assist level LV-C is allowed.

The allowable level ALV is an allowable maximum driving assist level.For example, in the location between a location K1 and a location K2,the allowable level ALV is a driving assist level LV-D. In the locationbetween a location K3 and a location K4, the allowable level ALV is adriving assist level LV-B. In the location between a location K5 and alocation K6, the allowable level ALV is a driving assist level LV-E.

The driving assist level determination device 40 acquires an evaluationvalue P for each point within a target range, based on the mapinformation MAP (map database MAP_DB). At the time, the driving assistlevel determination device 40 may acquire the evaluation value Passociated with the map information MAP as it is, or may process theevaluation value P associated with the map information MAP. The drivingassist level determination device 40 further determines the allowablelevel ALV for each point within the target range, by comparing theevaluation value P with the threshold TH.

In another example, as shown in FIG. 6 , the driving assist leveldetermination device 40 may acquire an evaluation value P for eachsection within a target range. For example, an average of the evaluationvalues P in the respective points included in a certain section iscalculated as the evaluation value P of the section. The driving assistlevel determination device 40 then compares the evaluation value P withthe threshold TH to determine an allowable level ALV for each sectionwithin the target range.

Thus, the driving assist level determination device 40 acquires theevaluation value P for each point or section within the target range,based on the map information MAP. The driving assist level determinationdevice 40 then determines the allowable level ALV for each point orsection within the target range, based on the evaluation value P.Specifically, the driving assist level determination device 40 sets theallowable level ALV to a first level LV-1 in the location where theevaluation value P is less than the threshold TH. The driving assistlevel determination device 40 also sets the allowable level ALV to asecond level LV-2 that is higher than first level LV-1 in the locationwhere the evaluation value P is equal to or more than the threshold TH.

A combination of a plurality of types of map information MAP may be usedfor the driving assist control. In that case, the evaluation values Pfor the respective types of the map information MAP are used, and two ormore allowable levels ALV are obtained for the same point or section.Setting of the threshold TH may be different among the respective typesof the map information MAP. The driving assist level determinationdevice 40 combines the allowable levels ALV to determine a finalallowable level ALV. For example, the driving assist level determinationdevice 40 selects the lowest allowable level ALV among the allowablelevels ALV.

As described in the foregoing, the driving assist level determinationdevice 40 automatically determines the allowable level ALV of thedriving assist control in a target range. The driving assist leveldetermination device 40 determines the allowable level ALV, based on theevaluation value P of the map information MAP in particular. This isbecause as the evaluation value P of the map information MAP is higher,the accuracy of the driving assist control using the map information MAPbecomes higher. Since the evaluation value P of the map information istaken into consideration, the allowable level ALV is appropriatelydetermined. As a result, the convenience for the driver of the vehicle 1is enhanced. Moreover, since an inadequate driving assist control isrestrained, safety is enhanced.

For example, when the evaluation value P of the map information MAP islow, the accuracy of the driving assist control based on the mapinformation MAP may also become low. In this case, the allowable levelALV also automatically becomes low, and therefore the driving assistcontrol is performed within a reasonable range. As a result, thediscomfort the driver feels for the driving assist control isrestrained. When the evaluation value P of the map information MAP ishigh, it becomes possible to conduct the driving assist control of ahigh level with sufficient accuracy. In this case, since the allowablelevel ALV becomes high, the convenience for the driver is enhanced.

1-4. Determination of Allowable Level Based on Map Information andIntervention Operation Information

During execution of the driving assist control, the driver of thevehicle 1 may perform “intervention operation.” The interventionoperation is performed by the driver to intervene the driving assistcontrol. For example, the intervention operation in the case of thedriving assist control at the driving assist level LV-C (steeringcontrol) includes steering operation by the driver. In another example,the intervention operation in the case of the driving assist control atthe driving assist level LV-D (steering control, acceleration control,and deceleration control) includes at least one of the steeringoperation, accelerator operation, and brake operation by the driver. Theintervention operation may include preparatory operation such as gripinga steering wheel, or putting a foot on a pedal.

The intervention operation represents the intention of a driver todrive. In the location where the intervention operation is performed,there is a possibility that a phenomenon undesirable for the drivingassist control may be present. Therefore, when generation of theintervention operation is further taken into consideration, it becomespossible to determine the allowable level ALV more appropriately.

FIG. 7 is a block diagram schematically showing another example of theconfiguration of the map information system 10 according to the presentembodiment. The description overlapped with the description in FIG. 3 isproperly omitted.

The intervention operation by the driver of the vehicle 1 is detected bya sensor mounted on the vehicle 1. In short, the driving environmentinformation 200 acquired by the information acquisition device 20 alsoincludes the information indicating that the intervention operation isperformed by the driver. An intervention operation location is thelocation where the intervention operation is performed. The interventionoperation location is indicated by intervention operation informationIOR.

The driving assist level determination device 40 acquires theintervention operation information IOR based on the driving environmentinformation 200. For example, the driving assist level determinationdevice 40 directly acquires the intervention operation information IORfrom the driving environment information 200. Alternatively, thedatabase management device 30 first acquires the intervention operationinformation IOR from the driving environment information 200, andregisters the intervention operation information IOR in the map databaseMAP_DB. Then, the driving assist level determination device 40 acquiresthe intervention operation information IOR from the map database MAP_DB.

The driving assist level determination device 40 retains theintervention operation information IOR, and utilizes the interventionoperation information IOR at the time of a subsequent travel of thevehicle 1. Specifically, the driving assist level determination device40 determines the allowable level ALV of the driving assist control,based on the evaluation value P of the map information MAP and theintervention operation information IOR (intervention operationlocation).

FIG. 8 is a conceptual view for describing an example of thedetermination method of the allowable level ALV. The format of FIG. 8 isthe same as the format described in FIGS. 5 and 6 before. A sectionbetween a location KS and a location KE is an intervention operationsection where the intervention operation is performed by a driver. Theintervention operation is not performed other than in the interventionoperation section. The location where the intervention operation is notperformed, that is, the location that is not the intervention operationlocation, is hereinafter called “normal location.”

In the example shown in FIG. 8 , the driving assist level determinationdevice 40 increases the threshold TH in the intervention operationlocation so as to be larger than that in the normal location. As aresult of the increase in the threshold TH, the allowable level ALV inthe intervention operation location tends to lower. For example, alocation K2 is a normal location and a location K4 is an interventionoperation location. Although the evaluation values P in the location K2and the location K4 are identical, the allowable level ALV (=LV−C) inthe location K4 becomes lower than the allowable level ALV (=LV−D) inthe location K2.

However, the increase in the threshold TH does not necessarily lower theallowable level ALV in the intervention operation location. For example,the location K1 is a normal location and a location K3 is anintervention operation location. The evaluation values P in the locationK1 and the location K3 are identical. Although a threshold TH-B in thelocation K1 is different from a threshold TH-B in the location K3, theirallowable levels ALV are both the driving assist level LV-B.

Thus, the driving assist level determination device 40 determines theallowable level ALV for each point or section within the target range,based on the evaluation value P of the map information MAP and theintervention operation location. On condition that the evaluation valuesP of the intervention operation location and the normal location areidentical, the allowable level ALV in the intervention operationlocation is equal to or less than the allowable level ALV in the normallocation. The intervention operation represents the intention of adriver to drive. In the intervention operation location, there is apossibility that a phenomenon undesirable for the driving assist controlmay be present. When the intervention operation location is taken intoconsideration, the allowable level ALV in the intervention operationlocation is determined more appropriately.

FIG. 9 is a conceptual view for describing another example of thedetermination method of the allowable level ALV. In the example shown inFIG. 9 , the driving assist level determination device 40 corrects theevaluation value P instead of increasing the threshold TH. Theevaluation value P after correction is hereinafter called “correctedevaluation value CP.” More specifically, the driving assist leveldetermination device 40 acquires the corrected evaluation value CP byreducing the evaluation value P in the intervention operation location.Meanwhile, the driving assist level determination device 40 maintainsthe evaluation value P in the normal location as it is, and uses it asthe corrected evaluation value CP.

The driving assist level determination device 40 compares the correctedevaluation value CP instead of the evaluation value P, with thethreshold TH. In short, the driving assist level determination device 40sets the allowable level ALV to the first level LV-1 in the locationwhere the corrected evaluation value CP is less than the threshold TH.The driving assist level determination device 40 also sets the allowablelevel ALV to the second level LV-2 that is higher than first level LV-1in the location where the corrected evaluation value CP is equal to ormore than the threshold TH.

The method shown in FIG. 9 can also provide the same effect as in themethod shown in FIG. 8 . In short, on condition that the evaluationvalues P in the intervention operation location and the normal locationare identical, the allowable level ALV in the intervention operationlocation is equal to or less than the allowable level ALV in the normallocation. Since the intervention operation location is taken intoconsideration, the allowable level ALV in the intervention operationlocation is determined more appropriately.

In yet another example, the database management device 30 may update,based on the intervention operation information IOR, the map databaseMAP_DB (map information MAP) so as to reduce the evaluation value P inthe intervention operation location. After updating the map databaseMAP_DB, the driving assist level determination device 40 determines theallowable level ALV based on the evaluation value P of the mapinformation MAP (see FIGS. 5 and 6 ). In this case, the interventionoperation location is reflected upon the evaluation value P of the mapinformation MAP, which can eliminate the necessity of changing thethreshold TH (see FIG. 8 ) or calculating the corrected evaluation valueCP (see FIG. 9 ).

1-5. Effects

As described in the foregoing, the driving assist level determinationdevice 40 according to the present embodiment automatically determinesthe allowable level ALV of the driving assist control in a target range.The driving assist level determination device 40 determines theallowable level ALV, based on the evaluation value P of the mapinformation MAP in particular. This is because as the evaluation value Pof the map information MAP is higher, the accuracy of the driving assistcontrol using the map information MAP becomes higher. Since theevaluation value P of the map information is taken into consideration,the allowable level ALV is appropriately determined. As a result, theconvenience for the driver of the vehicle 1 is enhanced. Moreover, sincean inadequate driving assist control is restrained, safety is enhanced.

Furthermore, the driving assist level determination device 40 maydetermine the allowable level ALV of the driving assist control based onthe intervention operation location. The intervention operationrepresents the intention of a driver to drive. In the location where theintervention operation is performed, there is a possibility that aphenomenon undesirable for the driving assist control may be present.Therefore, when the intervention operation location is taken intoconsideration, it becomes possible to more appropriately determine theallowable level ALV in the intervention operation location.

The driving assist controller 100 performs driving assist control at theallowable level ALV determined by the driving assist level determinationdevice 40. The map information MAP can effectively be utilized byperforming the driving assist control of an appropriate levelcorresponding to the evaluation value P of the map information MAP.

The map database MAP_DB, the database management device 30, and thedriving assist level determination device 40 may be mounted on thevehicle 1. In short, all the component members of the map informationsystem 10 may be mounted on the vehicle 1. In that case, the mapinformation system 10 automatically executes all the operations withinthe vehicle 1, the operations including acquisition of the drivingenvironment information 200, management of the map database MAP_DB basedon the driving environment information 200, determination of theallowable level ALV, and driving assist control based on the mapdatabase MAP_DB. Such a map information system 10 can also be referredto as “self-learning driving assist control system.” In the case whereautonomous driving control is performed as the driving assist control inparticular, such a map information system 10 can also be referred to as“self-learning autonomous driving system.”

It can be said that the map database MAP_DB is knowledge that is usefulfor the driving assist control. It can be said that the map informationsystem 10 according to the present embodiment automatically performsdetection, verification, and accumulation of the knowledge.

Hereinafter, the map information system 10 according to the presentembodiment will be described in more detail.

2. Configuration Example of Map Information System 2-1. ConfigurationExample of Driving Assist Controller

FIG. 10 is a block diagram showing a configuration example of thedriving assist controller 100 according to the present embodiment. Thedriving assist controller 100, which is mounted on the vehicle 1,includes a peripheral condition sensor 110, a vehicle location sensor120, a vehicle state sensor 130, a communication device 140, a humanmachine interface (HMI) unit 150, a travel device 160, and a controller170.

The peripheral condition sensor 110 detects the conditions around thevehicle 1. Examples of the peripheral condition sensor 110 may include acamera (imaging device), a laser imaging detection and ranging (LIDAR),and a radar. The camera images the conditions around the vehicle 1. TheLIDAR detects a target around the vehicle 1 using a laser beam. Theradar detects a target around the vehicle 1 using an electric wave.

The vehicle location sensor 120 detects the location and direction ofthe vehicle 1. For example, the vehicle location sensor 120 includes aglobal positioning system (GPS) sensor. The GPS sensor receives signalstransmitted from a plurality of GPS Satellites, and calculates thelocation and direction of the vehicle 1 based on the received signals.

The vehicle state sensor 130 detects the state of the vehicle 1. Thestate of the vehicle 1 includes a speed (vehicle speed), anacceleration, a rudder angle, and a yaw rate of the vehicle 1. The stateof the vehicle 1 also includes driving operation by the driver of thevehicle 1. The driving operation includes accelerator operation, brakeoperation, and steering operation.

The communication device 140 communicates with the outside of thevehicle 1. For example, the communication device 140 communicates withan external device outside the vehicle 1 through a communicationnetwork. The communication device 140 may perform a road-to-vehiclecommunication (V2I communication) with surrounding infrastructures. Thecommunication device 140 may perform vehicle-to-vehicle communication(V2V communication) with peripheral vehicles.

The HMI unit 150 is an interface for providing a driver with informationand receiving information from the driver. Specifically, the HMI unit150 includes an input device and an output device. Examples of the inputdevice may include a touch panel, a switch, and a microphone. Examplesof the output device may include a display device, and a speaker.

The travel device 160 includes a steering unit, a drive unit, and abraking unit. The steering unit steers a wheel. The drive unit is apower source that generates drive power. Examples of the drive unit mayinclude an electric motor and an engine. The braking unit generatesbraking force.

The controller 170 is a microcomputer including a processor 171 and astorage device 172. The controller 170 is also called an electroniccontrol unit (ECU). When the processor 171 executes control programsstored in the storage device 172, various processes are implemented bythe controller 170.

For example, the controller 170 acquires a necessary map information MAPfrom the map database MAP_DB. When the map database MAP_DB is installedin the vehicle 1, the controller 170 acquires the necessary mapinformation MAP from the map database MAP_DB. When the map databaseMAP_DB is present outside the vehicle 1, the controller 170 acquires thenecessary map information MAP through the communication device 140. Themap information MAP is stored in the storage device 172, and is properlyread and used.

The controller 170 also acquires the driving environment information200. The driving environment information 200 is stored in the storagedevice 172, and is properly read and used.

FIG. 11 shows an example of the driving environment information 200. Thedriving environment information 200 includes peripheral conditioninformation 210, vehicle location information 220, vehicle stateinformation 230, and distribution information 240.

The peripheral condition information 210 indicates the conditions aroundthe vehicle 1. The peripheral condition information 210 is informationobtained from the result of detection by the peripheral condition sensor110. For example, the peripheral condition information 210 includesimaging information obtained with the camera. The peripheral conditioninformation 210 also includes measurement information by a LIDAR or aradar. The peripheral condition information 210 may also include targetinformation regarding a target detected based on the imaging informationor measurement information. Examples of the target around the vehicle 1may include a stationary object, a characteristic object, a peripheralvehicle, and a pedestrian. The target information includes informationsuch as a relative position and a relative speed of a detected targetrelative to the vehicle 1. The controller 170 acquires the peripheralcondition information 210 based on the result of detection by theperipheral condition sensor 110.

The vehicle location information 220 indicates the location anddirection of the vehicle 1. The controller 170 acquires the vehiclelocation information 220 from the vehicle location sensor 120. Thecontroller 170 may further perform a well-known own-location estimation(localization) using the target information included in the peripheralcondition information 210 to increase the accuracy of the vehiclelocation information 220.

The vehicle state information 230 indicates the state of the vehicle 1.The state of the vehicle 1 includes a speed (vehicle speed), anacceleration, a rudder angle, and a yaw rate of the vehicle 1. The stateof the vehicle 1 further includes driving operation by the driver of thevehicle 1. The driving operation includes accelerator operation, brakeoperation, and steering operation. The controller 170 acquires thevehicle state information 230 from the vehicle state sensor 130.

The intervention operation includes at least one of the steeringoperation, the accelerator operation, and the brake operation by thedriver. The vehicle state information 230 also includes informationindicating that the intervention operation is performed by the driver.

The distribution information 240 is information obtained through thecommunication device 140. The controller 170 acquires the distributioninformation 240 by communicating with the outside using thecommunication device 140. For example, the distribution information 240includes road traffic information (such as construction sectioninformation, accident information, traffic control information, andtraffic congestion information) distributed from infrastructures. Thedistribution information 240 may include information on the peripheralvehicles obtained through V2V communication.

The controller 170 also performs driving assist control based on the mapinformation MAP and the driving environment information 200. Examples ofthe driving assist control may include autonomous driving control,path-following control, lane tracing assist control, collision avoidancecontrol, and adaptive cruise control. For such driving assist control,the controller 170 performs vehicle travel control as necessary. Thevehicle travel control includes steering control, acceleration control,and deceleration control. The controller 170 properly operates thetravel device 160 (the steering unit, the drive unit, and the brakingunit) to perform the steering control, the acceleration control, and thedeceleration control. It can be said that the controller 170 and thetravel device 160 constitute “vehicle travel controller” that performsvehicle travel control.

The case where the controller 170 performs autonomous driving control asan example of the driving assist control is considered. The controller170 generates a travel plan of the vehicle 1 based on the mapinformation MAP and the driving environment information 200. The travelplan includes a target route to a destination and local target tracks (atarget track in a lane, a target track for a lane change). The travelplan also includes a vehicle travel control plan for following thetarget tracks and avoiding obstacles in conformity with traffic rules.The controller 170 performs vehicle travel control such that the vehicle1 travels in accordance with the travel plan.

2-2. Configuration Example of Information Acquisition Device

The information acquisition device 20 acquires the driving environmentinformation 200. As shown in FIG. 10 , the peripheral condition sensor110, the vehicle location sensor 120, the vehicle state sensor 130, thecommunication device 140, and the controller 170 constitute theinformation acquisition device 20.

2-3. Configuration Example of Database Management Device 2-3-1. FirstConfiguration Example

FIG. 12 is a block diagram showing a first functional configurationexample of the database management device 30. In the first configurationexample, the map database MAP_DB is installed in the vehicle 1 (drivingassist controller 100). More specifically, the map database MAP_DB isstored in a storage device 180. The storage device 180 may be the sameas the storage device 172 of the controller 170. The controller 170(processor 171) manages the map database MAP_DB based on the drivingenvironment information 200. In short, the controller 170 functions asthe database management device 30.

2-3-2. Second Configuration Example

FIG. 13 is a block diagram showing a second configuration example of thedatabase management device 30. In the second configuration example, thedatabase management device 30 is implemented by an external device 300outside the vehicle 1. The external device 300 is a management server,for example.

More specifically, the external device 300 includes a storage device310, a processor 320, and a communication device 330. The storage device310 stores the map database MAP_DB. The communication device 330communicates with the communication device 140 on the vehicle 1 side.The processor 320 performs various information processes by executingcomputer programs stored in the storage device 310.

The information acquisition device 20 (controller 170) of the vehicle 1transmits the driving environment information 200 to the external device300 via the communication device 140. The processor 320 of the externaldevice 300 receives the driving environment information 200 from theinformation acquisition device 20 via the communication device 330. Theprocessor 320 manages the map database MAP_DB based on the drivingenvironment information 200.

The driving assist controller 100 (controller 170) of the vehicle 1requests map information MAP necessary for the external device 300 viathe communication device 140. The processor 320 of the external device300 reads the necessary map information MAP from the map databaseMAP_DB. The processor 320 then provides the map information MAP to thedriving assist controller 100 via the communication device 330.

2-3-3. Third Configuration Example

FIG. 14 is a block diagram showing a third configuration example of thedatabase management device 30. In the third configuration example, themap database MAP_DB is stored in the external device 300 as in the caseof the second configuration example. The database management device 30is implemented by the controller 170 of the vehicle 1. In short, thecontroller 170 (processor 171) remotely operates the map database MAP_DBon the side of the external device 300.

Specifically, the controller 170 acquires the driving environmentinformation 200 from the information acquisition device 20. Thecontroller 170 then registers or updates the map database MAP_DB basedon the driving environment information 200. At the time, the controller170 transmits a request signal REQ for requesting registration or updateto the external device 300 via the communication device 140. The requestsignal REQ contains information necessary for registration or update.The processor 320 of the external device 300 receives the request signalREQ via the communication device 330. The processor 320 then performsregistration or update of the map database MAP_DB in response to therequest signal REQ.

2-3-4. Fourth Configuration Example

The function of the database management device 30 may be distributed tothe controller 170 (processor 171) of the vehicle 1 and the processor320 of the external device 300.

The first to fourth configuration examples described above can also besummarized as shown below. More specifically, one processor (theprocessor 171 or the processor 320) or two or more processors (theprocessor 171 and the processor 320) execute processes as the databasemanagement device 30.

2-4. Configuration Example of Driving Assist Level Determination Device2-4-1. First Configuration Example

FIG. 15 is a block diagram showing a first configuration example of thedriving assist level determination device 40. In the first configurationexample, the map database MAP_DB is installed in the vehicle 1 (drivingassist controller 100). More specifically, the map database MAP_DB isstored in a storage device 180. The storage device 180 may be the sameas the storage device 172 of the controller 170. The controller 170(processor 171) functions as the driving assist level determinationdevice 40.

Specifically, the controller 170 determines a target range where thevehicle 1 travels, before or during execution of the driving assistcontrol. The controller 170 also acquires map information MAP relatingto the target range from the storage device 180 (map database MAP_DB).The controller 170 further acquires the intervention operationinformation IOR from the driving environment information 200 or thestorage device 180 (map database MAP_DB). The controller 170 thendetermines the allowable level ALV within the target range. Then, thecontroller 170 performs the driving assist control of the determinedallowable level ALV.

2-4-2. Second Configuration Example

FIG. 16 is a block diagram showing a second configuration example of thedriving assist level determination device 40. In the secondconfiguration example, the driving assist level determination device 40is implemented by the external device 300 outside the vehicle 1. Theconfiguration of the external device 300 is the same as theconfiguration shown in FIG. 13 described before.

The driving assist controller 100 (controller 170) of the vehicle 1determines a target range where the vehicle 1 travels, before or duringexecution of the driving assist control. The driving assist controller100 transmits the information on the target range to the external device300 via the communication device 140. The processor 320 of the externaldevice 300 receives the information on the target range via thecommunication device 330. Alternatively, the processor 320 of theexternal device 300 may determine the target range.

The processor 320 of the external device 300 acquires the mapinformation MAP relating to the target range from the storage device 310(map database MAP_DB). The processor 320 also acquires the interventionoperation information IOR from the driving environment information 200or the storage device 310 (map database MAP_DB). The processor 320 thendetermines the allowable level ALV within the target range. Theprocessor 320 notifies the information on the determined allowable levelALV to the driving assist controller 100 via the communication device330.

The driving assist controller 100 receives the information on thedetermined allowable level ALV via the communication device 140. Thedriving assist controller 100 performs the driving assist control of thenotified allowable level ALV.

2-4-3. Third Configuration Example

FIG. 17 is a block diagram showing a third configuration example of thedriving assist level determination device 40. In the third configurationexample, the map database MAP_DB is stored in the external device 300 asin the case of the second configuration example. The driving assistlevel determination device 40 is implemented by the controller 170 ofthe vehicle 1.

Specifically, the controller 170 determines a target range where thevehicle 1 travels, before or during execution of the driving assistcontrol. The controller 170 transmits a request signal REQ forrequesting provision of the map information MAP relating to the targetrange to the external device 300 via the communication device 140. Therequest signal REQ may further request provision of the interventionoperation information IOR.

The processor 320 of the external device 300 receives the request signalREQ via the communication device 330. The processor 320 reads from thestorage device 310 the request information requested in the requestsignal REQ. The processor 320 then transmits the request information tothe controller 170 via the communication device 330.

The controller 170 acquires the request information from the externaldevice 300 via the communication device 140. The controller 170 mayacquire the intervention operation information IOR from the drivingenvironment information 200. The controller 170 then determines theallowable level ALV within the target range. Then, the driving assistcontroller 100 performs the driving assist control of the determinedallowable level ALV.

2-4-4. Fourth Configuration Example

The function of the driving assist level determination device 40 may bedistributed to the controller 170 (processor 171) of the vehicle 1 andthe processor 320 of the external device 300.

The first to fourth configuration examples described above can also besummarized as shown below. More specifically, one processor (theprocessor 171 or the processor 320) or two or more processors (theprocessor 171 and the processor 320) execute processes as the drivingassist level determination device 40.

3. Registration of Intervention Operation Information

FIG. 18 is a flowchart showing registration of the interventionoperation information IOR by the database management device 30 accordingto the present embodiment. The database management device 30 acquiresthe driving environment information 200 from the information acquisitiondevice 20, during execution or after completion of the driving assistcontrol (step S310).

The driving environment information 200 includes the vehicle stateinformation 230. The vehicle state information 230 includes informationindicating that the intervention operation is performed by the driver.The database management device 30 acquires, based on the vehicle stateinformation 230, the location where the intervention operation isperformed as an intervention operation location. The database managementdevice 30 registers in the map database MAP_DB the interventionoperation information IOR indicating the intervention operation location(step S320).

4. Determination of Allowable Level of Driving Assist Control

Description is now given of the determination method of the allowablelevel ALV of the driving assist control by the driving assist leveldetermination device 40. Various examples are conceivable as thedetermination method of the allowable level ALV.

4-1. First Example

FIG. 19 is a flowchart showing a first example of the determinationmethod of the allowable level ALV. The first example corresponds to theexamples shown in FIGS. 5 and 6 described before.

In step S410A, the driving assist level determination device 40 acquiresmap information MAP relating to a target range from the map databaseMAP_DB.

In step S420, the driving assist level determination device 40 acquiresan evaluation value P for each point or section within the target range,based on the map information MAP. In the case of acquiring theevaluation value P for each section, an average of the evaluation valuesP in the respective points included in a section is calculated as theevaluation value P of the section, for example.

In subsequent step S450A, the driving assist level determination device40 performs a following determination process for each point or sectionwithin the target range. The driving assist level determination device40 compares the evaluation value P with the threshold TH (step S451A).When the evaluation value P is equal to or more than the threshold TH(step S451A; Yes), the driving assist level determination device 40 setsthe allowable level ALV to the second level LV-2 that is higher than thefirst level LV-1 (step S452). When the evaluation value P is less thanthe threshold TH (step S451A; No), the driving assist leveldetermination device 40 sets the allowable level ALV to the first levelLV-1 (step S453).

4-2. Second Example

FIG. 20 is a flowchart showing a second example of the determinationmethod of the allowable level ALV. The second example corresponds to theexample shown in FIG. 8 described before. The description overlappedwith the description of the first example is properly omitted.

In step S410B, the driving assist level determination device 40 acquiresmap information MAP relating to a target range from the map databaseMAP_DB. The driving assist level determination device 40 also acquiresintervention operation information IOR from the driving environmentinformation 200 or the map database MAP_DB. Step S420 is the same asstep S420 in the first example.

In step S430, the driving assist level determination device 40 increasesthe threshold TH in an intervention operation location so as to belarger than the threshold TH in a normal location that is not theintervention operation location.

Step S450A is the same as step S450A in the first example. However, thethresholds TH in the intervention operation location and the normallocation are different. As a result, on condition that the evaluationvalues P in the intervention operation location and the normal locationare identical, the allowable level ALV in the intervention operationlocation is equal to or less than the allowable level ALV in the normallocation.

4-3. Third Example

FIG. 21 is a flowchart showing a third example of the determinationmethod of the allowable level ALV. The third example corresponds to theexample shown in FIG. 9 described before. The description overlappedwith the description of the first and second examples is properlyomitted.

Step S410B and step S420 are the same as those in the second example. Instep S440 subsequent to step S420, the driving assist leveldetermination device 40 corrects the evaluation value P to acquire acorrected evaluation value CP. Specifically, the driving assist leveldetermination device 40 acquires the corrected evaluation value CP byreducing the evaluation value P in the intervention operation location.Meanwhile, the driving assist level determination device 40 maintainsthe evaluation value P in the normal location as it is, and uses it asthe corrected evaluation value CP.

In subsequent step S450B, the driving assist level determination device40 performs a following determination process for each point or sectionwithin the target range. Specifically, the driving assist leveldetermination device 40 compares the corrected evaluation value CP withthe threshold TH (step S451B). When the corrected evaluation value CP isequal to or more than the threshold TH (step S451B; Yes), the drivingassist level determination device 40 sets the allowable level ALV to thesecond level LV-2 that is higher than the first level LV-1 (step S452).When the corrected evaluation value CP is less than the threshold TH(step S451B; No), the driving assist level determination device 40 setsthe allowable level ALV to the first level LV-1 (step S453).

4-4. Fourth Example

FIG. 22 is a flowchart showing a fourth example of the determinationmethod of the allowable level ALV. The description overlapped with thedescription of the first example is properly omitted.

In step S390, the database management device 30 may update, based on theintervention operation information IOR, the map database MAP_DB (mapinformation MAP) so as to reduce the evaluation value P in theintervention operation location. Then, the same process as the firstexample is performed.

4-5. Fifth Example

A combination of a plurality of types of map information MAP may be usedfor the driving assist control. In that case, the evaluation values Pfor the respective types of the map information MAP are used, and two ormore allowable levels ALV are obtained for the same point or section.Setting of the threshold TH may be different among the respective typesof the map information MAP. The driving assist level determinationdevice 40 combines the allowable levels ALV to determine a finalallowable level ALV. For example, the driving assist level determinationdevice 40 selects the lowest allowable level ALV among the allowablelevels ALV.

5. Various Examples of Map Information

Description is now given of various examples of the map information MAPaccording to the present embodiment. The map information MAP includesmap information in various perspectives, in addition to general roadmaps or navigation maps. In the example shown in FIG. 23 , the mapinformation MAP includes stationary object map information BG_MAP,terrain map information TE_MAP, characteristic object map informationFE_MAP, and track map information TR MAP. Hereinafter, each of the mapinformation MAP will be described in detail.

5-1. Stationary Object Map Information BG_MAP

FIG. 24 is a conceptual view for describing an example of the stationaryobject map information BG_MAP. The stationary object map informationBG_MAP is map information MAP relating to stationary objects. Thestationary object map information BG_MAP indicates the location ofstationary objects. The stationary objects are immovable roadstructures, such as walls and guardrails. The stationary objects canalso be referred to as a background.

In the example shown in FIG. 24 , the space around the vehicle 1 isdivided into a large number of voxels VX. For each voxel VX, one dataset is prepared. Each data set includes a location [X, Y, Z], anoccupancy R, an evaluation value P, and evaluation information regardingthe voxel VX.

First, the occupancy R will be described. In one example, a LIDARincluded in the peripheral condition sensor 110 is used for detection ofa stationary object. The LIDAR sequentially outputs (scans) a laser beamtoward a plurality of directions. Based on reflective conditions of thelaser beam, the distance and the direction of reflecting points can becalculated. A LIDAR point group is a group of measure points (reflectionpoints) measured by the LIDAR.

When at least one laser beam reflects upon a certain voxel VX, ameasurement result value M_(i) relating to the voxel VX is set to “1”.When all the laser beams incident on a certain voxel VX pass through thevoxel VX without being reflected thereon, the measurement result valueM_(i) relating to the voxel VX is set to “0.” The measurement resultvalue M_(i)=“1” signifies that any object is present in the voxel VX.The measurement result value M_(i)=“0” signifies that no object ispresent in the voxel VX.

The LIDAR performs temporally repeated scanning with a laser beam.Therefore, measurement result values M_(i) that are temporallycontinuous are obtained with respect to the same voxel VX. The occupancyR relating to the voxel VX is defined as an average of the measurementresult values M_(i). When the number of times of measurement is N, theoccupancy R relating to the voxel VX is expressed by expression (1)below:

$\begin{matrix}{R = {\frac{1}{N}{\sum\limits^{N}M_{i}}}} & (1)\end{matrix}$

Whenever the vehicle 1 travels on the same road, the measurement resultvalues M relating to the voxel VX are newly obtained, and the occupancyR is calculated again. In other words, the occupancy R is updated.

The evaluation value P indicates “certainty” of the stationary objectmap information BG_MAP. In short, the evaluation value P indicates thecertainty of the presence or absence of a stationary object in thelocation [X, Y, Z]. For example, the evaluation value P takes a value inthe range of 0 to 1. As the evaluation value P is higher, there is ahigher possibility that the stationary object is present or absent inthe location [X, Y, Z].

The evaluation information is used to calculate the evaluation value P.For example, the evaluation information includes the number of times ofmeasurement N. When the number of times of measurement N is small, theevaluation value P is low. As the number of times of measurement Nbecomes larger, the evaluation value P becomes higher.

The evaluation information may include a variance V. The variance V is avariance in position of the measure points (reflection points) includedin a voxel VX. For example, when the surface of a wall is present in avoxel VX, a laser beam is reflected on the surface of the wall, so thatdistribution of the measure points becomes two-dimensional. In thiscase, the variance V is relatively small. When an indeterminate objectssuch as grass and smoke, are present in the voxel VX, the distributionof the measure points becomes three-dimensional, so that the variance Vbecomes large. As the variance V becomes larger, the evaluation value Pbecomes lower.

The evaluation information may include the aforementioned occupancy R.The occupancy value R=“1” signifies that any object is constantlypresent in a voxel VX. The object that is constantly present has a highpossibility of being a stationary object. Therefore, it may beconsidered to set the evaluation value P to be higher as the occupancy Rbecomes higher.

The database management device 30 generates and updates the stationaryobject map information BG_MAP based on the driving environmentinformation 200. Specifically, the driving environment information 200includes the peripheral condition information 210 (LIDAR measurementinformation) and the vehicle location information 220. The databasemanagement device 30 converts the peripheral condition information 210into an absolute coordinate system, based on the location and directionof the vehicle 1 indicated by the vehicle location information 220. Thedatabase management device 30 then generates or updates the data setrelating to each voxel VX, based on the peripheral condition information210 converted into the absolute coordinate system.

The information “there is a high possibility of the presence of astationary object” is useful. For example, such information is used toremove the stationary object from the LIDAR point group and to detectnon-stationary objects, such as pedestrians. The information “there is ahigh possibility of the absence of any stationary object” is alsouseful. This is because when a target is detected in a free space whereno stationary object is present, the detected target can be defined as anon-stationary object. Thus, the stationary object map informationBG_MAP may be used for recognition of a non-stationary object, forexample. When the non-stationary object is recognized, the drivingassist control for avoiding the non-stationary object can be performed.

5-2. Terrain Map Information TE_MAP

FIG. 25 is a conceptual view for describing one example of the terrainmap information TE_MAP. The terrain map information TE_MAP is mapinformation MAP relating to terrains. The terrain map information TE_MAPindicates a height (altitude) Z of a road surface at a location [X, Y].

In the example shown in FIG. 25 , a region around the vehicle 1 isdivided into a large number of cells. For each cell, one data set isprepared. Each data set includes a position [X, Y], a height Z, anevaluation value P, and evaluation information regarding the cell.

The LIDAR included in the peripheral condition sensor 110 is used forcalculation of the height Z of a road surface, for example.Specifically, a road surface point group indicative of the road surfaceis extracted from LIDAR point groups. Furthermore, the road surfacepoint group included in each cell is extracted. The height Z of the roadsurface at the location [X, Y] is calculated by interpolating theheights of the road surface points in the extracted road surface pointgroup. For example, an average of the heights of the road surface pointsin the extracted road surface point group is calculated as a height Z.The number of road surface points used for calculation of the height Zand the variance of the respective heights may be used as the evaluationinformation described later.

Whenever the vehicle 1 travels on the same road, the same road surfaceis repeatedly measured (detected), and the height Z of the same roadsurface is repeatedly calculated. In this case, an average or a weightedaverage of the heights Z calculated so far is used as the height Z. Inshort, whenever the same road surface is measured, the height Z isupdated. In the case of the weighted average value, the weight appliedto the latest height Z is set to be largest, for example.

The evaluation value P indicates “certainty” of the terrain mapinformation TE_MAP. In short, the evaluation value P indicates certaintyof the presence of a road surface at the location [X, Y] and the heightZ indicated by the terrain map information TE_MAP. For example, theevaluation value P takes a value in the range of 0 to 1.

The evaluation information includes the number of times of measurement,and the variance. The number of times of measurement includes at leastone of the number of times of calculation of the height Z and the numberof road surface points used for calculation of the height Z. Thevariance includes at least one of the variance of the calculated heightsZ and the variance in height of the respective road surface points usedfor calculation of the height Z. For example, when the number of timesof measurement is small, the evaluation value P is low. As the number oftimes of measurement becomes larger, the evaluation value P becomeshigher. As the variance becomes larger, the evaluation value P becomeslower. In another example, the evaluation value P may become lower, as adifference between the height Z and a height Z′ of an adjacent positionbecomes larger.

The database management device 30 generates and updates the terrain mapinformation TE_MAP based on the driving environment information 200.Specifically, the driving environment information 200 includes theperipheral condition information 210 (LIDAR measurement information) andthe vehicle location information 220. The database management device 30converts the peripheral condition information 210 into an absolutecoordinate system, based on the location and direction of the vehicle 1indicated by the vehicle location information 220. The databasemanagement device 30 then generates or updates the data set relating toeach cell, based on the peripheral condition information 210 convertedinto the absolute coordinate system.

The terrain map information TE_MAP is used as shown below. For example,with the terrain map information TE_MAP, it is possible to remove theroad surface from the LIDAR point groups, and to detect obstacles (forexample, falling objects) on the road surface. In another example, withthe terrain map information TE_MAP, it is possible to calculate a roadsurface gradient from the information on the height Z, and to plan avehicle travel control, such as acceleration and deceleration, based onthe road surface gradient. In still another example, it is possible todistinguish a travel area where the vehicle 1 can travel. In yet anotherexample, it is possible to find out a retreat area used to retreat thevehicle 1 in the case of the driving assist level LV-E (human-off)illustrated in FIG. 2 .

5-3. Characteristic Object Map Information FE_MAP

FIG. 26 is a conceptual view for describing one example of thecharacteristic object map information FE_MAP. The characteristic objectmap information FE_MAP is map information MAP relating to characteristicobjects. The characteristic object map information FE_MAP indicates thelocation of characteristic objects. Examples of the characteristicobjects may include linear objects, such as a lane marking and acurbstone, sheet objects, such as an indicator and a signboard, andpillar objects, such as a pole and a telegraph pole.

As one example, characteristic object map information FE_MAP relating toa lane marking LM is considered. The location of the lane marking LM isexpressed by locations [Xs, Ys, Zs] and [Xe, Ye, Ze] on both the ends ofthe lane marking LM. At least one of the camera and the LIDAR includedin the peripheral condition sensor 110 is used for calculation of thelocation of the lane marking LM, for example. Specifically, a roadsurface image indicative of a road surface is generated from cameraimaging information or LIDAR measurement information. Next, abinarization process or an edge detection process is performed toextract a lane marking LM from the road surface image. Then, thelocation of the lane marking LM is calculated based on the cameraimaging information or the LIDAR measurement information.

Whenever the vehicle 1 travels on the same road, the same lane markingLM is repeatedly measured (detected), and the same lane marking LM isrepeatedly calculated. In this case, an average or a weighted average ofthe locations calculated so far is used as the location. In short,whenever the same lane marking LM is measured, the location thereof isupdated. In the case of the weighted average value, the weight appliedto the latest location is set to be largest, for example. Whether thelane marking LM measured this time and a known lane marking LM areidentical or not is determined based on whether the lane marking LMmeasured this time is included in a prescribed range around the knownlane marking LM.

For each lane marking LM, one data set is prepared. In the exampleindicated in FIG. 26 , the data set includes the location of the lanemarking LM, the evaluation value P, and evaluation information. The sameconfiguration applies to the sheet objects or the pillar objects. Whenthe characteristic object is a sheet object, the data set may include acenter position, a width, a height, and a direction of the sheet object.When the characteristic object is a pillar object, the data set mayinclude an axial center position, a height, and a radius of the pillarobject.

The evaluation value P indicates “certainty” of the characteristicobject map information FE_MAP. In short, the evaluation value Pindicates the certainty of the presence of a characteristic object inthe location indicated by characteristic object map information FE_MAP.For example, the evaluation value P takes a value in the range of 0 to1.

The evaluation information includes the number of times of measurement,and variance in calculated location. For example, when the number oftimes of measurement is small, the evaluation value P is low. As thenumber of times of measurement becomes larger, the evaluation value Pbecomes higher. As the variance in calculated location becomes larger,the evaluation value P becomes lower.

The database management device 30 generates and updates thecharacteristic object map information FE_MAP based on the drivingenvironment information 200. Specifically, the driving environmentinformation 200 includes the peripheral condition information 210(camera imaging information, LIDAR measurement information) and thevehicle location information 220. The database management device 30converts the peripheral condition information 210 into an absolutecoordinate system, based on the location and direction of the vehicle 1indicated by the vehicle location information 220. The databasemanagement device 30 then generates or updates the data set regardingthe characteristic object, based on the peripheral condition information210 converted into the absolute coordinate system.

Such characteristic object map information FE_MAP is used in“own-location estimation (localization)” for enhancing the accuracy ofthe vehicle location information 220, for example. In the own-locationestimation, the location and direction of the vehicle 1 are estimated.Since the method of own-location estimation is well-known, the detaileddescription thereof is omitted. The driving assist control andgeneration and update of the map information MAP are performed based onthe high-accuracy vehicle location information 220 obtained byown-location estimation.

As shown in FIG. 26 , the evaluation information may includeown-location estimation error. Hereinafter, description is given of amethod for determining the evaluation value P of the characteristicobject map information FE_MAP from the perspective of the own-locationestimation error. Although description is given of the location of thevehicle 1 in the following example, the description also applies to thedirection of the vehicle 1.

In the example shown in FIG. 27 , characteristic objects F_(i) (i=1 to3) are present around the vehicle 1. The characteristic object F₁ is alane marking, the characteristic object F₂ is a signboard, and thecharacteristic object F₃ is a pole. These characteristic objects F_(i)are detected based on the peripheral condition information 210 (cameraimaging information, LIDAR measurement information). Measured distancesd_(i) to the characteristic objects F_(i) can also be obtained from theperipheral condition information 210. Here, a lateral distance is usedas a measured distance d₁ to the lane marking, and a longitudinaldirection distance is used as a measured distance d₂ to the signboard.The measured distances d_(i) are assumed to have a prescribedmeasurement error σ_(i).

The locations of the characteristic objects F_(i) are already registeredin the characteristic object map information FE_MAP. Own-locationestimation is performed based on the locations and the measureddistances d_(i) of the characteristic objects F_(i) registered in thecharacteristic object map information FE_MAP.

FIG. 28 shows the result of own-location estimation. A location PE isestimated as a location of the vehicle 1. A beltlike region B_(i) inFIG. 28 is defined from a location, a measured distance d_(i), and ameasurement error σi of a characteristic object F_(i) registered in thecharacteristic object map information FE_MAP. More specifically, thebeltlike region B_(i) is distanced by the measured distance d_(i) fromthe location of the characteristic object F_(i), and the beltlike regionB_(i) has a width of 2σ_(i). It can be said that the accuracy of theown-location estimation is higher, as an overlapping region where theregions B₁ to B₃ overlap is larger. On the contrary, when theoverlapping region is small, the accuracy of own-location estimation islow, and the own-location estimation error is large.

For quantitative estimation of the own-location estimation error EL, adistance de_(i) between the location of the characteristic object F_(i)registered in the characteristic object map information FE_MAP and theestimation location PE is considered. FIG. 28 illustrates a distancede_(i) between the characteristic object F₁ and the estimation locationPE. The own-location estimation error EL is expressed by followingexpression (2), for example:

$\begin{matrix}{{EL} = \sqrt{\sum\limits_{i}{\frac{\left( {d_{i} - {de}_{i}} \right)^{2}}{\sigma_{i}^{2}}/{\sum\limits_{i}\frac{1}{\sigma_{i}^{2}}}}}} & (2)\end{matrix}$

One of the factors of the error EL is an error of the location of thecharacteristic object F_(i) registered in the characteristic object mapinformation FE_MAP. Therefore, based on the error EL, the evaluationvalue P of the characteristic object map information FE_MAP can bedetermined. For example, as the error EL is larger, the evaluation valueP becomes lower, whereas as the error EL is smaller, the evaluationvalue P becomes higher.

5-4. Track Map Information TR MAP

FIG. 29 is a conceptual view for describing one example of the track mapinformation TR MAP. The track map information TR MAP is map informationMAP relating to the track TR of the vehicle 1. More specifically, thetrack map information TR MAP indicates the location of a track TR forthe vehicle 1 to travel in the conditions where no obstacle is present.

The database management device 30 generates and updates the track mapinformation TR MAP based on the driving environment information 200 orother map information MAP.

Typically, the track TR extends through the center of a lane. Thedatabase management device 30 acquires the location of a lane marking LMthat defines a lane from the peripheral condition information 210 or thecharacteristic object map information FE_MAP. The database managementdevice 30 calculates the center position of the lane from the locationof the lane marking LM, and sets the center position of the lane as thetrack TR.

When it is difficult to calculate the center position of the lane, thedatabase management device 30 acquires the location of a curbstone. Thelocation of the curbstone can be acquired from the peripheral conditioninformation 210, the terrain map information TE_MAP, or thecharacteristic object map information FE_MAP. The database managementdevice 30 sets the location that is in a constant distance from thecurbstone as the track TR.

Alternatively, the database management device 30 may set the track TRbased on an actual track at the time of manual driving. The actual trackat the time of manual driving is obtained from the vehicle locationinformation 220. For example, the database management device 30 sets anaverage of two or more actual tracks as the track TR. Thus, the track TRbecomes close to the actual track at the time of manual driving. As aresult, the discomfort of the driver when the vehicle 1 travels alongthe track TR is reduced.

As shown in FIG. 29 , the evaluation value P is associated with eachlocation [X, Y, Z] on the track TR. The evaluation value P indicates“certainty” of the track map information TR MAP. For example, theevaluation value P takes a value in the range of 0 to 1.

The evaluation information may include the actual track at the time ofmanual driving. The evaluation value P becomes high in the locationwhere the track TR is close to the actual track. The evaluation value Pbecomes low in the location where the track TR deviates from the actualtrack. When two or more actual tracks are present, an average of theactual tracks is compared with the track TR, for example. Alternatively,the evaluation value P is calculated based on a sum total of the amountsof deviation of the respective actual tracks from the track TR.

The evaluation information may include the aforementioned centerposition of the lane. The evaluation value P becomes high in thelocation where the track TR is close to the center position of the lane.The evaluation value P becomes low in the location where the track TRdeviates from the center position of the lane.

The evaluation information may include a curvature of the track TR. Theevaluation value becomes low in the location where the curvature islarge.

The track map information TR MAP is used for preparation of a travelplan of the vehicle 1, for example. The travel plan includes a targettrack for the vehicle 1 to travel. The driving assist controller 100sets the track TR registered in the track map information TR MAP as atarget track. The driving assist controller 100 then performs vehicletravel control such that the vehicle 1 follows the target track. Whenthe track map information TR MAP is used, it is not necessary to detecta lane marking LM and calculate the center position of the lane one byone. Therefore, a calculation load is reduced. The target track of asection beyond a sensor detection range can also be acquired beforehand.These features are desirable in terms of efficiency of the drivingassist control.

5-5. Other Map Information

Examples of other map information MAP may include traffic signal mapinformation indicating the location of traffic signals, and road markingmap information indicating the location of road markings. Examples ofthe road markings may include a stop line, a temporary stop line, and apedestrian crossing.

The map information MAP may include aforementioned LIDAR measurementinformation, camera imaging information, and road surface imageinformation. When acquiring these pieces of information, the databasemanagement device 30 registers the acquired information in the mapdatabase MAP_DB.

6. Map Information Update Process

The database management device 30 according to the present embodimentupdates the map information MAP. The map information update process bythe database management device 30 will be described below.

6-1. Basic Flow

FIG. 30 is a flowchart showing the map information update process. Theprocess flow shown in FIG. 30 is repeatedly executed for each constantcycle.

In step S310, the database management device 30 acquires the drivingenvironment information 200 from the information acquisition device 20.

In step S320, the database management device 30 converts the peripheralcondition information 210 into an absolute coordinate system, based onthe location and direction of the vehicle 1 indicated by the vehiclelocation information 220.

In step S330, the database management device 30 acquires the latest mapinformation MAP, based on the driving environment information 200. Thedatabase management device 30 acquires the latest map information MAP,based on the peripheral condition information 210 converted into theabsolute coordinate system or the vehicle location information 220 inparticular. The content of the respective map information MAP and theevaluation value P are as described in Section 5.

In step S340, the database management device 30 updates the existing mapinformation MAP with use of the latest map information MAP obtained instep S330. At the time, in addition to the base map information in themap information MAP, the evaluation information and the evaluation valueP are also updated.

It is expected that the evaluation value P (quality) of the mapinformation MAP is improved whenever the vehicle 1 travels on the sameroad. As the evaluation value P of the map information MAP becomeshigher, it becomes possible to conduct the driving assist control of ahigher level. The map information MAP can effectively be utilized byperforming the driving assist control of an appropriate levelcorresponding to the evaluation value P of the map information MAP.

6-2. First Modification

In some locations, the error of the driving environment information 200may be large. For example, the error of the peripheral conditioninformation 210 increases due to noise. In another example, in thelocation where the own-location estimation error EL is large, the errorof the vehicle location information 220 also increases. When the mapinformation update process is performed using the driving environmentinformation 200 having a large error, the evaluation value P may end uplowering.

Accordingly, the database management device 30 performs tentative updateof the map information MAP, and calculates a tentative evaluation valueP. Furthermore, the database management device 30 extracts the locationwhere the tentative evaluation value P is equal to or less than aprescribed value as an excluding location. The database managementdevice 30 then performs the map information update process again usingthe driving environment information 200 that excludes the excludinglocation.

Alternatively, the database management device 30 may compare theevaluation values P before and after the map information update process.When the evaluation value P after the update process is lower than theevaluation value P before the update process, the database managementdevice 30 cancels the update and restores the original map informationMAP.

The first modification can prevent undesirable decrease of theevaluation value P of the map information MAP.

6-3. Second Modification

In a second modification, the driving environment information 200unsuitable for the map information update process is excludedbeforehand. For example, the driving environment information 200,acquired in the section where occurrence of sudden steering is frequent,is not suitable for the map information update process. In anotherexample, the driving environment information 200 acquired in rainyweather is not suitable for the map information update process.

From such a perspective, the database management device 30 calculates“suitability ST” indicating a suitable degree of the driving environmentinformation 200 suitable for the map information update process. Shownbelow are driving environment (factors) causing calculation of a lowsuitability ST.

(a) Lateral acceleration or longitudinal acceleration exceeding athreshold (basis information: vehicle location information 220, vehiclestate information 230).

(b) Curvature of a travel locus of the vehicle 1 exceeding a threshold(basis information: vehicle location information 220)

(c) Traveling locus of the vehicle 1 becoming discontinuous (basisinformation: vehicle location information 220)

(d) Rainfall, snowfall (basis information: peripheral conditioninformation 210 (camera imaging information, LIDAR measurementinformation))

(e) Nighttime, backlight (basis information: peripheral conditioninformation 210 (camera imaging information))

(f) Occurrence of stain on the camera lens (basis information:peripheral condition information 210 (camera imaging information))

(g) Density of the LIDAR point group being less than a threshold (basisinformation: peripheral condition information 210 (LIDAR measurementinformation))

(h) Occurrence of stain on the LIDAR (basis information: peripheralcondition information 210 (LIDAR measurement information))

The database management device 30 calculates the suitability ST based onthe basis information. As the degree of each factor becomes larger, thesuitability ST becomes lower. The database management device 30 comparesthe suitability ST with a suitability threshold, and excludes thedriving environment information 200 having the suitability ST less thanthe suitability threshold. In other words, the database managementdevice 30 performs the map information update process with use of thedriving environment information 200 having the suitability ST equal toor more than the suitability threshold. This makes it possible toprevent undesirable decrease of the evaluation value P of the mapinformation MAP.

6-4. Third Modification

The database management device 30 may delete a portion of the existingmap information MAP where the evaluation value P is low. For example,the database management device 30 extracts from the existing mapinformation MAP a portion where the evaluation value P is equal to orless than a prescribed value, as a deletion target. The databasemanagement device 30 then deletes the deletion target from the existingmap information MAP. This makes it possible to maintain the quality ofthe map information MAP constant.

6-5. Fourth Modification

The database management device 30 may perform the map information updateprocess only for the location where the evaluation value P is low in theexisting map information MAP. For example, the database managementdevice 30 extracts from the existing map information MAP a region wherethe evaluation value P is equal to or less than a prescribed value as anupdate target region. The database management device 30 then performsthe map information update process using the driving environmentinformation 200 corresponding to the update target region. This makes itbecomes possible to efficiently improve the evaluation value P of themap information MAP with a small calculation amount.

6-6. Fifth Modification

A large change may occur in real environment at certain timing. Forexample, the shape of a road may drastically change due to roadrepairing or natural disasters. When the map information update processis repeatedly performed after such a change timing, the evaluation valueP may gradually decrease in the change occurrence region. Accordingly,the database management device 30 accumulates a history of theevaluation value P. When there is a region where the evaluation value Pcontinuously reduced a prescribed number of times, the databasemanagement device 30 defines the region as the change occurrence region.The database management device 30 deletes the map information MAPrelating to the change occurrence area. This makes it possible torestrain deterioration in quality of the map information MAP.

7. Display of Allowable Level of Driving Assist Control

As described in the foregoing, the driving assist level determinationdevice 40 determines the allowable level ALV that is the driving assistlevel allowed when the vehicle 1 travels in a target range. The drivingassist controller 100 performs driving assist control of the allowablelevel ALV determined by the driving assist level determination device40. At the time, the driving assist controller 100 (controller 170) maydisplay the allowable level ALV on the display device of the HMI unit150.

For example, the case where the vehicle 1 travels to the destinationalong a target route is considered. The driving assist controller 100sets the target route for the vehicle 1 to travel. The driving assistlevel determination device 40 determines the allowable levels ALV alongthe target route. The driving assist controller 100 performs the drivingassist control such that the vehicle 1 travels along the target route.At the time, the driving assist controller 100 (controller 170) displaysa transition of the allowable level ALV along the target route from acurrent location or current time on the display device of the HMI unit150. It is not necessarily needed to display all the allowable levelsALV up to the destination at once. The driving assist controller 100 mayselectively display only the allowable levels ALV of a limited rangeincluding the current location.

FIG. 31 shows an example of the display of the allowable level ALV. Ahorizontal axis represents time or location along a target route, and avertical axis represents the allowable level ALV along the target route.In the example shown in FIG. 31 , temporal or locational transition ofthe allowable level ALV is displayed as a graph. An icon indicative ofthe driver operation (example: eyes-off, hands-off, hands-on) in eachallowable level ALV may be displayed. The driver can easily recognizethe change in level of future driving assist control in advance.

FIG. 32 shows another example of the display of the allowable level ALV.In the example shown in FIG. 32 , only the icons indicative of lapse oftime and driver operation in the respective allowable levels ALV aredisplayed. For example, in a period from time T1 to T2, the allowablelevel ALV is LV-D. At time T2, the allowable level ALV is switched toLV-B. In a period from time T2 to T3, the allowable level ALV is LV-B.At time T3, the allowable level ALV is switched again to LV-A. Thedriver can easily recognize the change in level of future driving assistcontrol in advance.

FIG. 33 is a conceptual view showing still another example of thedisplay of the allowable level ALV. In the example shown in FIG. 33 ,the driving assist controller 100 displays the map on the displaydevice. The driving assist controller 100 further displays a transitionof the target route and the allowable level ALV so as to be superimposedon the map. The height of the allowable level ALV is distinguishable bychanging line fonts or colors. For example, in a section from thecurrent location to a location P1, the allowable level ALV is LV-D. In asection from the location P1 to a location P2, the allowable level islowered to LV-C. In a section from the location P2 to a location P3, theallowable level ALV is further lowered to LV-B. In the location P3, theallowable level ALV is raised back to LV-D. The icons indicative of thedriver operation in each allowable level ALV may be displayed. Theinformation shown in FIG. 33 may be displayed together with theinformation shown in FIG. 31 or 32 .

When a plurality of target route candidates is present, the drivingassist controller 100 may display the target route candidates togetherwith the transition of the allowable level ALV. The driver selects adesired target route by referring to the transition of the allowablelevel ALV. The desired target route is selected by using the inputdevice of the HMI unit 150, for example. The driving assist controller100 performs the driving assist control such that the vehicle 1 travelsalong the desired target route.

Thus, the transition of the allowable level ALV along the target routefrom the current location or current time is displayed, which enablesthe driver to recognize the change in future driving assist levels inadvance. Therefore, the driver can cope with the change in the drivingassist level well in advance. This is preferable in terms ofconvenience.

What is claimed is:
 1. A management device comprising circuitryprogrammed to: acquire, based on driving environment informationindicating a driving environment of a vehicle, with an intention of adriver to intervene in a driver assistance control when a phenomenonundesirable for the driver assistance control is present, interventionoperation information indicating an intervention operation location thatis a location where an intervention operation is performed, theintervention operation being an operation performed by the driver of thevehicle to intervene in driving assist control during execution of thedriving assist control, the driving environment information includinginformation indicating that the intervention operation has beenperformed, acquire, based on a map information, an evaluation value foreach point or section within a target range, the map information beingused for driving assist control for assisting driving of the vehicle andbeing associated with the evaluation value indicating a certainty of themap information for each location in an absolute coordinate system,determine, based on the evaluation value and the intervention operationlocation, an allowable level of the driving assist control that isallowed when the vehicle travels in the target range for each point orsection within the target range, and perform the driving assist controlof the allowable level of the driving assist control, based on thedriving environment information and the map information, wherein theevaluation value is set to be higher as an occupancy is higher, and theoccupancy is an average value of a plurality of measurement resultvalues relating to a voxel around the vehicle when at least one laserbeam of a peripheral condition sensor of the vehicle reflects upon thevoxel, wherein when a combination of a plurality of types of mapinformation is used for the driving assist control, the evaluation valueof each of the plurality of types of map information is used to obtaintwo or more allowable levels for a same point or section within thetarget range, and the two or more allowable levels are combined todetermine a final allowable level of the driving assist control, whereinthe allowable level of the driving assist control is equal to or lessthan the allowable level of the driving assist control in a normallocation that is not the intervention operation location, on conditionthat the evaluation values in the intervention operation location andthe normal location are identical, and wherein the circuitry is furtherconfigured to: maintain the evaluation value in a normal position whilereducing the evaluation value in the intervention operation location toacquire a corrected evaluation value, set the allowable level of thedriving assist control to a first level in a location where thecorrected evaluation value is less than a threshold, and set theallowable level of the driving assist control to a second level that ishigher than the first level in a location where the corrected evaluationvalue is equal to or more than the threshold.
 2. The management deviceaccording to claim 1, wherein the circuitry is further configured to:increase the threshold in the intervention operation location so as tobe larger than the threshold in a normal position.
 3. The managementdevice according to claim 1, further comprising a display device mountedon the vehicle, wherein: the circuitry is further configured todetermine the allowable level of the driving assist control along thetarget route for the vehicle to travel; and the driving assistcontroller is configured to display on the display device a transitionof the allowable level of the driving assist control from a currentlocation or current time.
 4. The management device according to claim 3,wherein the driving assist controller is configured to display on thedisplay device the target route and the transition of the allowablelevel of the driving assist control so as to be superimposed on a map.5. A driver assist control method comprising: acquiring, based ondriving environment information indicating a driving environment of avehicle, with an intention of a driver to intervene in a driverassistance control when a phenomenon undesirable for the driverassistance control is present, intervention operation informationindicating an intervention operation location that is a location wherean intervention operation is performed, the intervention operation beingan operation performed by the driver of the vehicle to intervene indriving assist control during execution of the driving assist control,the driving environment information including information indicatingthat the intervention operation has been performed, acquiring, based ona map information, an evaluation value for each point or section withina target range, the map information being used for driving assistcontrol for assisting driving of the vehicle and being associated withthe evaluation value indicating a certainty of the map information foreach location in an absolute coordinate system, determining, based onthe evaluation value and the intervention operation location, anallowable level of the driving assist control that is allowed when thevehicle travels in the target range for each point or section within thetarget range, and performing the driving assist control of the allowablelevel of the driving assist control, based on the driving environmentinformation and the map information, wherein the method furthercomprises setting the evaluation value to be higher as an occupancy ishigher, the occupancy being an average value of a plurality ofmeasurement result values relating to a voxel around the vehicle when atleast one laser beam of a peripheral condition sensor of the vehiclereflects upon the voxel, wherein when a combination of a plurality oftypes of map information is used for the driving assist control, theevaluation value of each of the plurality of types of map information isused to obtain two or more allowable levels for a same point or sectionwithin the target range, and the two or more allowable levels arecombined to determine a final allowable level of the driving assistcontrol, wherein the determining of the allowable level of the drivingassist control includes setting the allowable level of the drivingassist control to be equal to or less than the allowable level of thedriving assist control in a normal location that is not the interventionoperation location, on condition that the evaluation values in theintervention operation location and the normal location are identical,and wherein the method further comprises: maintaining the evaluationvalue in a normal position while reducing the evaluation value in theintervention operation location to acquire a corrected evaluation value,setting the allowable level of the driving assist control to a firstlevel in a location where the corrected evaluation value is less than athreshold, and setting the allowable level of the driving assist controlto a second level that is higher than the first level in a locationwhere the corrected evaluation value is equal to or more than thethreshold.
 6. The driver assist control method according to claim 5,wherein the determining of the allowable level of the driving assistcontrol further includes increasing the threshold in the interventionoperation location so as to be larger than the threshold in a normalposition.
 7. The driver assist control method according to claim 5, themethod further comprising: determining the allowable level of thedriving assist control along the target route for the vehicle to travel;and displaying on a display device a transition of the allowable levelof the driving assist control from a current location or current time.8. The driver assist control method according to claim 7, the methodfurther comprising displaying on the display device the target route andthe transition of the allowable level of the driving assist control soas to be superimposed on a map.
 9. A non-transitory computer-readablemedium storing instructions, the instructions comprising: one or moreinstructions that, when executed by one or more processors of a device,cause the one or more processors to: acquire, based on drivingenvironment information indicating a driving environment of a vehicle,with an intention of a driver to intervene in a driver assistancecontrol when a phenomenon undesirable for the driver assistance controlis present, intervention operation information indicating anintervention operation location that is a location where an interventionoperation is performed, the intervention operation being an operationperformed by the driver of the vehicle to intervene in driving assistcontrol during execution of the driving assist control, the drivingenvironment information including information indicating that theintervention operation has been performed, acquire, based on a mapinformation, an evaluation value for each point or section within atarget range, the map information being used for driving assist controlfor assisting driving of the vehicle and being associated with theevaluation value indicating a certainty of the map information for eachlocation in an absolute coordinate system, determine, based on theevaluation value and the intervention operation location, an allowablelevel of the driving assist control that is allowed when the vehicletravels in the target range for each point or section within the targetrange, and perform the driving assist control of the allowable level ofthe driving assist control, based on the driving environment informationand the map information, wherein the evaluation value is set to behigher as an occupancy is higher, and the occupancy is an average valueof a plurality of measurement result values relating to a voxel aroundthe vehicle when at least one laser beam of a peripheral conditionsensor of the vehicle reflects upon the voxel, when a combination of aplurality of types of map information is used for the driving assistcontrol, the evaluation value of each of the plurality of types of mapinformation is used to obtain two or more allowable levels for a samepoint or section within the target range, and the two or more allowablelevels are combined to determine a final allowable level of the drivingassist control, wherein the instructions, when executed by the one ormore processors of the device, further cause the one or more processorsto set the allowable level of the driving assist control to be equal toor less than the allowable level of the driving assist control in anormal location that is not the intervention operation location, oncondition that the evaluation values in the intervention operationlocation and the normal location are identical, and wherein theinstructions, when executed by the one or more processors of the device,further cause the one or more processors to: maintain the evaluationvalue in a normal position while reducing the evaluation value in theintervention operation location to acquire a corrected evaluation value,set the allowable level of the driving assist control to a first levelin a location where the corrected evaluation value is less than athreshold, and set the allowable level of the driving assist control toa second level that is higher than the first level in a location wherethe corrected evaluation value is equal to or more than the threshold.10. The non-transitory computer-readable medium according to claim 9,wherein the instructions, when executed by the one or more processors ofthe device, further cause the one or more processors to: increase thethreshold in the intervention operation location so as to be larger thanthe threshold in a normal position.